package com.xxlie.core.common;

import org.dozer.DozerBeanMapper;
import org.dozer.loader.api.BeanMappingBuilder;

import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import static org.dozer.loader.api.TypeMappingOptions.mapEmptyString;
import static org.dozer.loader.api.TypeMappingOptions.mapNull;

/**
 * 简单封装Dozer, 实现深度转换Bean<->Bean的Mapper.实现:
 *  
 * 1. 持有Mapper的单例. 
 * 2. 返回值类型转换.
 * 3. 批量转换Collection中的所有对象.
 * 4. 区分创建新的B对象与将对象A值复制到已存在的B对象两种函数.
 * 
 * @author xxlie.com
 * @version 2013-01-15
 */
public class BeanUtils {

	/**
	 * 持有Dozer单例, 避免重复创建DozerMapper消耗资源.
	 */
	private static DozerBeanMapper dozer = new DozerBeanMapper();

	/**
	 * 基于Dozer转换对象的类型.
	 */
	public static <T> T map(Object source, Class<T> destinationClass) {
		return dozer.map(source, destinationClass);
	}

	/**
	 * 基于Dozer转换Collection中对象的类型.
	 */
	@SuppressWarnings("rawtypes")
	public static <T> List<T> mapList(Collection sourceList, Class<T> destinationClass) {
		List<T> destinationList = new ArrayList<>();
		for (Object sourceObject : sourceList) {
			T destinationObject = dozer.map(sourceObject, destinationClass);
			destinationList.add(destinationObject);
		}
		return destinationList;
	}

	/**
	 * 基于Dozer将对象A的值拷贝到对象B中.
	 */
	public static void copy(Object source, Object destinationObject) {

		WeakReference<DozerBeanMapper> weakReference = new WeakReference<>(new DozerBeanMapper());
		DozerBeanMapper mapper = weakReference.get();
		assert mapper != null;
		mapper.addMapping(new BeanMappingBuilder() {
			@Override
			protected void configure() {
				mapping(source.getClass(), destinationObject.getClass(), mapNull(false), mapEmptyString(false));
			}
		});
		mapper.map(source, destinationObject);
		mapper.destroy();
		weakReference.clear();

	}
}